Pilot weld nut and method of making the same



E. E. HOWE 3,045,736

PILOT WELD NUT AND METHOD OF MAKING THE SAME July 24, 1962 3Sheets-Sheet 1 Original Filed April 23, 1949 INVENTOR. Ea/"Z E Han e.

July 24, 1962 HQwE 3,045,736

PILOT WELD NUT AND METHOD OF MAKING SAME Cfiginal Filed April 23, 1949 5Sheets-Sheet 2 C ng 765 mu I! w WHIHIIJ m .16. /'9 INVENTOR. 1 far/IHON/6".

July 24, 1962 E. E. HOWE 3,045,736

PILOT WELD NUT AND METHOD OF MAKING THE SAME Original Filed April 23,1949 3 sheets'sheet 5 INVENTOR. EarZ Z Hon 6.

United States Patent 3,045,736 PILOT WELD NUT AND METHOD OF MAKING THESAME Earl E. Howe, Chicago, Ill. Continuation of application Ser. No.89,190, Apr. 23, 1949. This application June 23, 1958, Ser. No. 743,67415 Claims. (Cl. 151-41.7)

This is a continuation of applications Serial No. 89,190, filed April23, 1949, Which is a continuation-inpart of Serial No. 560,984, filedOctober 30, 1944, both now abandoned, and Serial No. 420,863, filedApril 5, 1954, now abandoned.

My invention resides in the field of weld elements or connectingelements of the weld nut type, and in a method which can be appliedequally well to either nuts 'or boltheads as desired.

A primary object of my invention is to provide a new and improved methodof making uniform discrete weld elements of the pilot type, wherein theresulting element has a pilot or guiding portion for socketing the ele-.ment into an opening, and the weld element may be made from a discreteblank such as a standard nut by a single application of pressure or asingle pressure stroke.

Another object of my invention is to provide a new and improved methodof making a pilot weld element in such a manner that the finaldimensions of the element are accurately determined.

Another object of my invention is to provide a method of making a pilotnut so that welding projections are formed around the pilot and setbackor below the top surface of the pilot a predetermined distance andaccurately positioned relative to an undistorted reference surface ofthe blank from which it is made.

Another object of my invention is to provide a method of making a pilotweld nut of the above type in which the welding projections have theirpoints slightly blunted and positioned in a plane normal to the axis ofthe weld nut.

Another object of my invention is to provide a method ofmaking a pilotnut of the above type in which one surface of the nut will besubstantially un-marred and unaffected by a single pressure operation sothat the resulting nut will not fuse to its electrode during asubsequent welding operation.

Another object of my invention is to provide a pilot weld nut formed bythe above method.

Other objects will appear from time to time in the ensuing specificationand drawings in which:

FIGURE 1 is a plan view of a new and improved pilot weld nut resultingfrom my method;

FIGURE 2 is a side view of the pilot nut shown in FIGURE 1;

FIGURE 3 is a sectional view taken along line 3--3 of FIGURE 1;

FIGURE 4 is a sectional view taken along line 4-4 of FIGURE 1;

FIGURE 5 is a plan view of a standard nut positioned in the diespreparatory to the pressure operation;

FIGURE 6 is a sectional view taken along lines 6-6 of FIGURE 5;

FIGURE 7 is a sectional view taken along lines 77 of FIGURE 6;

FIGURE 8 is a sectional view similar to FIGURE 6 but on an enlargedscale showing the die mechanism engaging a standard nut at the end of adie pressure operation;

FIGURE 9 is asectional view similar to FIGURE 8 taken diagonally acrossthe corners of the nut and the die mechanism;

FIGURE 10 is a perspective view of the nut in FIG- URES 1 through 9;

FIGURE 11 is a modified form of the pilot nut showing slightly modifieddie mechanisms;

FIGURE 12 is a plan view of the nut formed in FIG- URE 11;

FIGURE 13 is a side view of the nut in FIGURE 12 showing its initialrelation with a perforated piece of metal (diagrammatically illustrated)to which it is to be welded;

FIGURE 14 is a view similar to FIGURE 11 and showing a method of makinga pilot nut as in FIGURE 12 but with blunted tips on the weldingprojections;

FIGURE 15 is a plan view of the pilot nut formed by the methodillustrated in FIGURE 14;

FIGURE 16 is a side elevational View of the nut shown in FIGURE 15;

FIGURE 17 is a sectional view, similar to FIGURE 8, showing a modifieddie mechanism and method;

FIGURE 18 is a horizontal section taken along the line 1818 of FIGURE17;

FIGURE 19 is a plan view of a modified form of pilot weld nut formed bythe method illustrated in FIG- URES 17 and 18;

FIGURE 20 is a sectional view taken along the line 20-2tl of FIGURE 19;and

FIGURE 21 is a sectional view taken along the line 21-41 of FIGURE 19.

In FIGURE 5 I have shown a blank such as a standard nut, indicatedgenerally at 10, positioned in a reciprocating die mechanism. Such ablank has generally flat, parallel, square end surfaces 12 and 14 ofequal area, intersecting generally flat side surfaces 16 in lateraledges, corners l8, and a centrally disposed threaded bore 20, the axisof which is generally normal to the surfaces 12 and 14'. A nut blank ofthis type, of course, is conventional and readily obtainable in grosslots on the open market relatively cheaply.

A discrete nut blank, such as shown in FIGURES 5 and 6, is positioned byitself in a pressure or working zone or station between the opposed diesof a reciprocating press, the lower die of which including a post-likeelement 22 firmly resting on any suitable supporting structure or frame.The post is surrounded on three sides by a U-shaped pad element 24supported on a resilient rubber unit 26 so that the pad can easily bemoved up and down. Normally the upper surface of the pad extendsslightly above the upper surface of the post, as shown in FIGURE 6,forming a three-sided pocket 28 open on one side, as shown in FIGURE 5,for accurately positioning the nut blank preparatory to the formation ofthe weld nut. Thus the nut blank can be fed along the surface of thepost into the three-sided pocket and will be accurately positionedtherein by the pad. Of course, the dies may be opened wider than I haveshown in FIGURE 6 to facilitate insertion of the nut blanks, andmultiple dies can be used so as to form a plurality of pilot weld nutson each stroke of the press.

The upper die includes a cage element 30 surrounding the pocket andhaving a generally open cylindrical bore 32 of a greater diameter thanthe width of the pocket. Disposed and removably held within the bore 'byany suitable means is a replaceable punch element 34 having a workengaging face 36 of a special configuration positioned over the pocketand engageable with a nut blank positioned therein during closing of thepress.

The punch element has an open passage 38. The

work engaging face 36 includes an annular fiat surface 40 surroundingthe passage 38. Surrounding the surface 40 and concentric with it is afrusto-conical surface 42. Surrounding this surface and concentrictherewith is annular flat surface 44 which extends to the outer edge ofthe punch element.

In FIGURES 8 and 9 I have shown the nut after it has been formed by thedie mechanism with the punch element still in engagement with it. Anysuitable drive mechanism can be provided to force the upper die d wninto engagement with the nut blank to form the resulting pilot nut.During its initial downward movement the cage 30 engages the pad 24 anddepresses the rubber element 26, the relative positions being best shownin FIGURE 6. Before the upper edge of the pad passes below the uppersurface of the post the annular die surface 40 of the punch 34 engagesthe upper end surface 12 of the nut blank inwardly of the corners 18. Asthe upper die progressively moves downwardly in a single unitarymovement the conical surface 42 next engages the blank inwardly of thecorner portions and works the metal of the blank and finally the outerannular surface 44 engages the metal of the blank at the corners andcooperates with the surface 42 to form the projections 54. Thedownwardly moving punch element 34 displaces and deforms the metal ofthe blank at one end thereof outwardly of the pilot 48 both axially andlaterally outwardly. The post 22 supports the lower end surface of theblank so that the metal at such end is not deformed. Thus the displacedmetal must flow laterally.

To prevent the nut blank from substantially losing its originaldimensions, the cage has a cylindrical inner confining surface or wall46 which opposes and limits the lateral flow at the corners, as shown inFIGURE 9.

The metal at the center of the nut blank around the threaded bore isgenerally unopposed and free from metall deforming pressure and fromdisplacement and forms a circular pilot 48, being accommodated in thepassage 38 of the punch. The shape of the pilot 48 will, of course,conform to the shape of passage 38, and if desired the cross section ofpassage 38 may be square or hexagonal, or otherwise to form acorrespondingly shaped pilot. The inner annular surface 40 of the punchswork engaging face forms an annular, generally flat, depressed area 50on the nut which surrounds the pilot. The outer edge of this annulararea overlaps the lateral edges of the nut slightly as shown in FIGURES1 and 10.

The conical surface 42 of the punch only contacts the blank across andinwardly of the corners 18 to form disconnected conical surfaces 52faced generally toward the pilot.

The corners are formed by the cooperation of surfaces 42 and 44 intouniform projections 54 of equal height which project outwardly slightlyas shown in FIGURES 4 and 9 and are blunted at 56 so that the projectionformed at each corner has a fiat, blunt engaging end or surface, and sothat the blunted ends 56 of all of the projections 54 all lie in a planenormal to the axis of the nut.

The axial distance between the annular surfaces 40 and 44 on the punchis imparted to the nut blank. Therefore the axial distance between theannular zone or area St) and the general plane of the blunt projections56 is generally this same axial distance. In effect, the annular area 44lowers each of the projections 54 below the top surface of the pilot 48a predetermined distance as shown in FIGURES 4 and 9.

In FIGURES 11 through 13 I have shown a modified form of the pilot nutin which a blank such as a standard square nut is confined betweenopposed dies 58 and 60, the lower die having a square bore 62 to form apilot portion 63 and the upper die having a pocket to receive the bodyof the blank. The lower die has raised cutting edges 64 whichsimultaneously cut across one end surface inwardly of all of the cornersof the blank deform- 4 ing the corner material thereof both axially andlaterally as shown in FIGURES 12 and 13 to form uniform weldingprojections 68 of equal height. A confining wall 66 on the upper dieprohibits substantial lateral deformation, and the dies engage eachother after projections 68 have been forced away from or beyond thesides of the pilot 63 due to penetration of the cutting edges 64 intothe body of the blank a predetermined distance. FIG- URE 13 shows theinitial relation of the pilot weld nut of FIGURE 12 to an aperturedpiece of metal diagrammatically illustrated at 70 to which the nut is tobe welded, with the pilot 63 projecting through the aperture in themetal 70 and with the tips of the welding projections 68 all contactingone surface of the piece 70.

In FIGURES l2 and 13 it can be seen that the pilot is substantiallysquare rather than round like the pilot in the species of FIGURES 1through 10. The nut in FIG- URES 11 and 13 could be formed to have around pilot, but a square pilot is desirable in certain circumstances.

The use, operation and function of my invention are as follows:

My invention is broadly a method of forming a pilot weld nut per se sothat the resulting nut will have: predetermined outside or lateraldimensions, a pilot formed in the body of the nut, uniform projectionsof equal height at each of the corners disposed around the pilot andprojecting in the same direction as the pilot, the common plane of theprojections being axially spaced from the upper surface of the pilot andblunted points on the projections to effect accurate welding. It is verydesirable to make a pilot weld nut of the above type from a blank suchas a standard or conventional nut which can be purchased in largequantities on the open market at favorable prices. A method thatuniformly produces an accurate special design of nut from a standard nutblank is highly desirable because special forged strips of metal orrolled sections will not be required. All a weld nut manufacturer has todo is to buy standard nuts and deform them according to the abovemethod, and an efficient and accurate pilot weld nut is produced.

Referring first to the species of FIGURES 1-10, the three work engagingsurfaces on the punch are very important. The inner annular surface ineffect forms the pilot by depressing and deforming axially the metalthat surrounds the pilot but without deforming the metal of the pilot 48or the threaded bore. The frusto-conical work engagement surface 42deforms the corner portions both axially and laterally and works themetal into welding points or projections between it and the surroundingwall of the cage. The outer annular surface 44 on the punch blunts thepoints or projections and displaces them into a plane a predetermineddistance below the upper surface of the pilot, which is the original endsurface of the nut.

The confining wall 46 of the cage 30 confines the metal at the cornersof the nut body and prevents it from flowing too far laterally so thatthe resulting pilot weld nut can still be used in conventional hopperfeeding equipment even though slightly deformed laterally. It should beunderstood that the confining wall can be adjusted as desired in size ormade with any suitable dimension to determine accurately the outsidedimensions of the resulting pilot nut, for example as shown in FIGS. 17to 21 hereof.

It is very desirable that the welding projections be blunted toaccurately form and position such projections so that when the weld nutis positioned against a plate with an electrode placed against thesurface 14, the nut will not rock, and all four blunt surfaces on theprojections will firmly engage the metal plate and current will flowevenly through each projection and will fuse it solidly to the plate. Ifone point is higher than the other, all of the current will flow throughthe uneven point and an uneven, poor quality connection will result withintense sparking.

The post supporting the lower surface of the standard nut blank does notmar it in any way. It can be seen in FIGURES 2 through 4 and in FIGURE13 that one surface of the pilot nut is substantially unchanged. This isthe surface against which the electrode is applied and thenut will nothave a tendency to fuse to the electrode .through 9. Thus, in FIGURES14, 15 and 16 I show a modified form of the weld nut shown in FIGURE 12with welding projections 168 having blunted tips 169, and a method ofmaking the same.

In making the pilot nut of FIGURES l5 and 16 a standard nut blank isconfined between two opposed dies 1553 and 160, the lower die having asquare bore 162 to form a pilot 163, and the upper die having a pocketto receive the body of the blank. The lower die has raised cutting edges164 which cut across one end surface of the blank inwardly of thecorners of the blank, deforming the corner material both axially andlaterally as shown. A confining wall 166 on the upper die prohibitssubstantial lateral deformation, and the dies engage each other afterthe projections 168 have been forced away from the pilot 163 due to thepenetration of the cutting edges 164 into the body of the blank apredetermined distance. The lower die 160 is formed outwardly of eachcutting edge 164 with flat surfaces 171 which engage the tips of theprojections 168 and blunt the same, thereby forming flat contact areas169 at the tips of the welding projections 168, such areas 169 being inacommon plane which is normal to the axis of the nut so that all fourblunt surfaces 169 will firmly engage the metal plate to which the nutis to be welded.

If the resulting nut has a tendency to stick or hang in the punch, asuitable knockout could, of course, be easily provided.

In FIGURES 17 to 21 there are illustrated a modified apparatus andmethod for forming a pilot weld nut like FIGURE 1 but in which theoverall dimensions of the pilot nut are the same as those of thestandard blank from which the pilot weld nut is made. Thus, the pilotweld nut as shown in FIGURES 19, 20 and 21 is essentially the same asthat disclosed in FIGURES l to 4 and 10 and is formed by the samemethod, except that the lateral dimensions of the finished nut as shownin FIGURES 19, 2.0 and 21 are the same as the blank from which the pilotweld nut is made.

Themethod and apparatus of FIGURES 17 and 18 essentially involve, inaddition to the steps involved in forming the nut of FIGURE 1, theperformance of an additional step so as to trim or shear from the weldnut as shown in FIGURE 1 the displaced metal of the blank whichoverhangs the sides of the original blank illustrated in dotted line inFIGURE 1. Thus, in FIGURES 17 and 18, where the parts of the apparatusare the same as those used in the forming of the nut shown in FIGURE 1,the same reference characters are employed and hence there is nonecessity for repeating here the method and apparatus previouslydescribed for forming the weld not shown in FIGURES l-.4 and 10.

In the case of FIGURE 17, the punch comprises two parts, namely thepunch element 34A and the punch element 343. The punch element 34A inall significant respects is the same in construction and function as thepunch element 34, and willin the apparatus as illustrated in FIGURE17form a pilot weld element essentially as illustrated inFIGURE 1. Inother words, the pilot weld nut illustrated in the apparatus in FIGURE17 corresponds in all significant respects with the pilot weld nut shownin FIGURES 14 and 10.

The punch element 34A is disposed within the punch element 343 and hassurfaces 240, 242 and 244 corresponding essentially with surfaces 40, 42and44 of punch element 34, except-for the omission of portions of theannular surface 240 which, if provided, would overhang the nut blank. Inother words, the lateral dimensions of the surface 244 do not exceed thelateral dimensions of the nut blank. The punch 34A is also provided witha passage 38 like the punch 34 for accommodating the pilot 48 during theformation of the weld nut.

The punch element 343 comprises a plurality of shearing or trimmingtools 245, each of which is provided with a cutting or trimming edge247. The cutting edges of the shearing ortrimming tool portion of punchelement are adapted after the formation of the pilot weld nut as shownin FIGURE 1 to trim or shear from the nut body the outwardly laterallydisplaced metal which overhangs the original sides of the nut blank, andfor this purpose the punch element 343 after it moves downwardly withthe punch element 34A to the positionvshown in FIGURE 17 is movabledownwardly relatively to the punch 34A so as to trim the excess metalabove referred to, indicated at 249 in FIGURE 17, thereby finishing thepilot weld nut to the size and shape as illustrated in FIGURES 19, 2dand 21. Suitable provision (not shown) is made for the removal of thetrimmed portions from the die, such as by the use of an air blast.

It should be noted in all of the embodiments shown that the weldingprojections, including the tips thereof, not only are accurately formedduring the formation of the pilot weld nut, but also are uniformly andaccurately positioned with reference to the threaded bore of the nut sothat the finished pilot weld nut is accurately made. Thus the processdisclosed and claimed permits the economical manufacture of uniform,accurately made pilot weld nuts from blanks such as standard nuts,although the process is not limited to the use of standard nuts asblanks. The process normally produces an accurately made pilot weld nutin which the welding projections are formed and accurately locatedduring their formation with respect to an undistorted reference surfaceof the blank from which the nut is made.

While I have shown and described the preferred forms of my invention, itshould be understood that numerous alterations, substitutions, changesand modifications can be made without departing from the fundamentaltheme of the invention, and I therefore wish that my invention beunrestricted except as by the appended claims.

I claim:

1. A discrete weld nut formed from flat square stock having cornerportions partly sheared from the remainder of the stock downwardly fromone side thereof, the sheared corner portions being spaced apart toprovide portions of the original edges of the nut intact, the shearedcorner portions being formed downwardly below the said one side of thenut, and each having the upper surface thereof inclined upwardly andoutwardly to leave the original corners of the nut at a higher elevationthan the remainder of the upper surface of the corner portions so as toform uniform welding projections at the outer corners of the nut.

2. The structure of claim 1 in which the sheared corner portions arestraight.

3. The structure of claim 1 in which the welding projections formed atthe corner portions have sharp points.

4. A discrete weld nut formed from generally flat square stock with athreaded bore and having portions sheared from the remainder of thestock downwardly from one side thereof while leaving such remainder toform a pilot and said side at its original elevation, said portionsincluding the corners, the sheared portions at the corners being formeddownwardly and disposed around said pilot below the said one side of thenut, and having the upper surfaces thereof inclined upwardly andoutwardly to leave the ends of the sheared portions at the corners ofthe not at a higher elevation than the remainder of the sheared portionsinwardly of the corners so as to form uniform welding projections aroundsaid pilot at the outer corners of the nut, the said ends of saidwelding projections being disposed in a common plane which is axiallyspaced from the plane of said side, said sheared portions at the cornersbeing spaced apart so as to leave portions of the original flat edges ofthe nut intact.

5. A discrete weld nut formed from flat square stock having cornerportions partly sheared from the undistorted remainder of the stockdownwardly from one side thereof, the sheared corner portions beingspaced apart to provide portions of the original flat edges of the nutintact, the sheared corner portions being formed downwardly below thesaid one side of the nut and having the upper surface thereof inclinedupwardly and outwardly to leave the sheared portions at the corners ofthe nut at a higher elevation than the remainder of the upper surface ofthe sheared portions so as to form welding projections, said weldingprojections being disposed at the outermost corners of the nut, the topsof said welding projections consisting of deformed metal and beingdisposed in a common plane normal to the axis of the nut.

6. A method of forming a discrete pilot weld element by a singleapplication of pressure from a polygonal sided blank having generallyparallel end surfaces of equal area intersecting generally flat sides inlateral edges with the fiat sides intersecting each other in continuousaxial edges, the sides and end surfaces forming corners at the outermostperiphery of said blank, and connecting means axially disposed centrallyof the blank; the method including the steps of supporting the blank byeither one of its end surfaces while dissociated from the part to whichthe weld element is to be welded and while so supported; directing axialpressure of metal deforming intensity in three stages and pressure areasagainst the other of its end surfaces, the first area being annular, thefirst and second pressure areas being applied within the corners of theblank and spaced radially outward from the connecting means and thethird pressure area being applied to such corners; continuing theapplication of such axial pressure to displace the material of the blankincluding such corners axially in the direction in which such pressureis applied and laterally while allowing only limited predeterminedlateral flow of the flat sides at the corners adjacent said othersurface; and discontinuing such axial pressure when the first pressurearea has formed a central pilot surrounded by an annular surface whichintersects the sides of the blank between the corners a substantialdistance axially removed from the original plane of said other endsurface; when the second pressure area has formed a sloping surface ateach corner rising from the said annular surface and generally facingthe pilot so that the corners of the blank form axially extendinguniform projections at the outer corners of the nut rising above saidannular surface and spaced from said pilot; and when the third pressurearea has deformed and axially displaced the tips of such projections sothat they lie in a common plane between the end surfaces generallyperpendicular to the axis, all while maintaining the axial dimension ofthe weld element through the pilot and the connecting means the same asthe original axial dimension of the blank, and the overall dimensionsand shape of such weld element within limits such that the discrete weldelement produced is of a size and shape suitable for use in hopper feedequipment.

7. A method of forming a discrete pilot weld nut by a single applicationof pressure from a standard nut blank of uniform thickness axiallyhaving corners at the outermost periphery of the blank and a centralaxially extending bore, such method including the steps of applyingaxial pressure of metal deforming intensity at areas on one end of theblank spaced outwardly from the bore while the blank is dissociated fromthe part to which the weld nut is to be welded, increasing the area ofapplied pressure outwardly toward and including such corners at said oneend so as to displace such end corners of the blank at such areas onlyaxially in the direction in which such pressure is applied and laterallyoutwardly, confining the lateral displacement at said one end topreselected dimensions while maintaining a Zone surrounding md includingthe bore of the nut blank free from metal deforming pressure and frommetal displacement, and discontinuing such pressure when the corners areformed as uniform welding projections at the outer corners of the nutwith their tips surrounding a central pilot and lying in a common planeparallel to and between the original end faces of the blank and at theoutermost periphery thereof, all while maintaining the overall axialdimension of the pilot nut within the original axial dimension of theblank, and the overall dimensions and shape of such weld element withinlimits such that the discrete weld element produced is of a size andshape suitable for use in hopper feed equipment.

8. The method of claim 7 in which die pressure is applied to the tips ofthe projections to blunt them.

9. The mehod of forming a discrete pilot weld nut, by a singleapplication of pressure, from an initially polygonal sided blank havingend surfaces of equal area and corners at the outermost periphery ofsaid blank and an axial bore, which includes the following steps:supporting either one of such end surfaces against axial displacementwhile the blank is dissociated from the part to which the weld nut is tobe welded and while so supported; directing single unitary pressure ofmetal deforming intensity axially against the other end surface and itscorners of the blank, in a circumferential zone of pressure locatedwithin and including the corners of the blank and around and radiallyoutwardly of the bore, while allowing preselected lateral flow of thematerial at the corners at said other end surface outwardly beyond theoutermost periphery of the original body contour of the blank; directingand limiting such axial pressure to form axially extending uniformcorner welding projections at the outer corners of the nut having outertips lying in a predetermined plane at the outermost periphery of saidblank, closer to the original surface against which the pressure isdirected than is a plane common to the inner portions of the cornerprojections, and with both said planes generally perpendicular to theaxis ofthe pilot Weld nut; continuing the application of axial pressureuntil both said last-mentioned planes lie between the planes of the endsurfaces of the blank, While maintaining an inner part of that endsurface against which the axial pressure was directed free from suchpressure in a zone surrounding and including the bore, and atsubstantially its original distance from the supported end surface ofthe original blank; and confining and discontinuing the application ofaxial pressure before metal flow distorts the central bore, all whilemaintaining the overall axial dimension of the pilot weld nut Within theoriginal axial dimension of the blank, and the overall dimensions andshape of such weld element within limits such that the discrete weldelement produced is of a size and shape suitable for use in hopper feedequipment.

10. A method of forming a discrete pilot weld nut from a standard squarenut blank having corners and a threaded axial bore which includes thesteps of applying axial pressure of metal deforming intensity at areason one end of the blank spaced outwardly from said bore while the blankis dissociated from the part to which the weld nut is to be Welded,increasing the area of applied pressure outwardly toward and includingthe corners so as to displace the material at such end and the cornersthereof both axially and laterally outwardly while maintaining the axialdimension of said blank through the portion thereof which forms saidbore, confining the lateral displacement to preselected dimensions, anddiscontinuing the pressure when the corners are formed into uniformaxial Welding projections at the outer periphery of the blank with theirtips surrounding a central pilot and lying in a common plane parallel toand between the original end faces of the blank, all while maintainingthe discrete weld element produced of a size and shape within limitssuitable for use in hopper feed equipment.

11. The method of forming a square discrete pilot weld nut withconnecting means axially disposed centrally thereof from a blank ofuniform axial thickness having parallel end surfaces of equal areaintersecting a continuous Peripheral surface which extends continuouslyaxially between Such end surfaces and is disposed normal theretoandformslateral edges therewith, such method includingthe steps of:supporting the blank by itself while dissociated from the part to whichthe weld nut is to be welded and while so supported; directing axialpressure of metal deforming intensity against one of such end surfacesof the blank, in a zone of pressure which includes all of such endsurface to and including the outermost periphery of the blank except acentral part located around and adjacent the axis of said blank therebyto form an annular, generally flat surface which intersects the sides ofthe blank, while allowing preselected lateral flow of the material ofthe blank at the sides thereof outwardly beyond the Original bodycontour of the blank and a central pilot projecting upwardly from andsurrounded by said annular surface; directing and limiting such axialpressure to form uniform welding projections at the outer corners ofsaid nut having their tips lying in a predetermined plane, closer to theoriginal surface against which the pressure is directed than is theplane of said flat surface, and with both said planes generallyperpendicular to the axis of the weld nut; and continuing theapplication of such axial pressure until said last-mentioned planes liebetween the planes of the original end surfaces of the blank, all whilemaintaining the overall axial dimensions of the pilot nut within theoriginal axial dmension of the blank and the overall dimensions andshape of such weld nut within such limits that the discrete weld nutproduced is of a size and shape suitable for use in hopper feedequipment.

l2. A method of forming a discrete pilot weld nut from a discrete nutblank having corners at the outer periphery thereof and a threaded axialbore which includes the steps of applying axial pressure of metaldeforming intensity to areas on either end of the blank spaced outwardlyfrom said bore while the blank is dissociated from the part to which theweld nut is to be welded, increasing the area of applied pressureoutwardly toward and including such corners at the outer periphery ofthe blank so as to displace the corners at such end axially whilemaintaining the axial dimension of said blank through the portionthereof which forms said bore to form a central pilot including suchbore, and discontinuing such pressure when the corners are formed intouniform axial welding projections at the outer periphery of the pilotend of the blank projecting from the blank in the same direction as thepilot and with the tops of such projections surrounding such pilot andlying in a common plane parallel to and between the original end facesof the blank and normal to the axis of said bore, all while controllingthe lateral flow of the material of the blank at the sides thereof so asto maintain the discrete weld element produced of a size and shapeapproximating that of the blank and within limits suitable for use inhopper feed equipment, said method being characterized in that saidwelding projections are simultaneously so formed in one continuousoperation and uniformly disposed with respect to an undistorted fiatreference surface of the blank.

13. The method of forming a polygonal discrete pilot weld element from adiscrete blank of uniform axial thickness having parallel end surfacesof equal area intersecting a continuous peripheral surface which extendscontinuously axially between such end surfaces and is disposed normalthereto and forms lateral edges therewith, such method including thesteps of: supporting the blank by itself while dissociated from the partto which the weld element is to be welded and while so supported;directing axial pressure of metal deforming intensity symmetricallyagainst either of said end surfaces of the blank, in a zone of pressurewhich includes all of such end surface to and including the outermostperiphery of the blank except a central part located around and adjacentthe axis of said blank thereby to form a central pilot projecting fromand surrounded by an annularly extending surface which intersects thesides forming the outer periphery of said blank; directing and limitingsuch axialpressure to simultaneously form uniform welding projectionsextending in the same direction as and surrounding said pilot anddisposed at the corners at the outer periphery of ,saidtelement, andwith the ends of such projections lying in a common plane, closer to theoriginal surface against which the pressure is directed than is theplane of said annularly extending surface, and with both of said planesgenerally perpendicular to the axis of said pilot; and continuing theapplica tion of such axial pressure until said last-mentioned planes liebetween the planes of the original end surfaces of the blank, all whilemaintaining the overall axial dimensions of the pilot element within theoriginal axial dimension of the blank and restraining the lateral fiowof the material of the blank at the sides thereof so as to maintain theoverall dimensions and shape of such weld element within such limitsthat the discrete weld element produced is of a size and shape suitablefor use in hopper feed equipment.

14. That method of forming a polygonal discrete pilot weld nut from adiscrete blank having parallel end surfaces of equal area intersecting acontinuous peripheral surface which extends continuously axially betweensuch end'surfaces and is normal thereto and forms lateral edgestherewith, such method including the steps of: supporting the blank byitself while dissociated from the part to which the weld nut is to bewelded and While so supported directing axial pressure of metaldeforming intensity symmetrically against either of said end surfaces ina plurality of pressure zones so as to axially displace metal of theblank at the periphery downwardly relative to a central part of theblank thereby to form a central pilot, applying radial outward pressureto portions of the axially displaced metal while applying said axialpressure, directing and limiting such axial and radial pressure tosimultaneously form uniform welding projections extending in the samedirection as and surrounding said pilot and disposed at the corners atthe outer periphery of said weld nut, and with the tips of saidprojections lying in a common plane axially below the end face of saidpilot; all while maintaining the overall axial dimension of the pilotweld nut within the original axial dimension of the blank andrestraining the lateral flow of the material of the blank at the sidesthereof so as to maintain the overall dimensions and shape of such weldnut produced within limits such that it is of a size and shape suitablefor use in hopper feed equipment.

15. That method of forming a discrete polygonal pilot weld nut from adiscrete blank having parallel end surfaces of equal area intersecting acontinuous pehipheral surface which extends continuously axially betweensuch end surfaces and is disposed normal thereto and forms lateral edgestherewith, said method including the steps of: supporting the discreteblank by either one of its end surfaces while dissociated from the partto which the resulting weld nut is to be Welded and while so supported;directing axial pressure of metal deforming intensity in a series ofstages and pressure areas against the other of its end surfaces, saidpressure areas being symmetrically disposed, applying such pressure todisplace the material of the blank subjected to such pressure areas onlyin the direction in which such pressure is applied and later-allyoutwardly while limiting such lateral flow and discontinuing such axialpressure when one of said pressure areas has formed a central pilotsurrounded by an annular surface which intersects the sides of the weldnut between the corners thereof a substantial distance axially removedfrom the plane of the end face of said pilot, when a second pressurearea has formed at each corner of the weld nut an axially extendinguniform projection rising from said annular surface and spaced from thepilot and with the tips of said projections lying in a common planebetween the end surfaces of the nut and generally perpendicular to theaxis thereof, all while maintaining the axial dimension of the weld nutthrough the pilot Within the original axial dimension of the blank andthe overall dimensions and shape of such Weld nut 5 within limits suchthat it is of a size and shape suitable for use in hopper feedequipment.

References Cited in the file of this patent UNITED STATES PATENTSAlmdale Sept. 15, 1936 Double Mar. 1, 1938 Howe Oct. 7, 1952 Muchy Sept.22, 1953 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo. 3,045,736 July 24, 1962 Earl E. Howe It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

1: uniform Column 7, line 15, after "form" inser Signed and sealed this30th day of October 1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Commissioner of Patents Attesting Officer

